"This type of swell means that there can be periods of 5-10 minutes of small surf before a large set rolls though - this can easily catch out rock-fishers or people walking around rocks, learner-surfers, people swimming in unpatrolled areas and boats crossing bars".

The same conditions were responsible for the trouble a motor launch got into on the Ballina bar, the subsequent capsizing of the Marine Rescue boat and dramatic rescue by the Ballina Jet Boat about two kilometres off shore.

The rescue crews have been nominated for bravery awards for their efforts and won the praise of Surf Life Savinf NSW.

"It was a gallant effort by the jet boat crew to perform the rescue in such dangerous conditions and at night. It could have been a very tragic outcome if it wasn't for their skill and selflessness," Far North Coast emergency services officer Jimmy Keough said.

UPDATE 1.45pm: THE CREW of the Ballina Marine Rescue boat that capsized this morning while coming to the aid of a motor cruiser in distress have been nominated for bravery awards.

Richmond Local Area Command duty officer acting Inspector Jackie Lilley said police contacted Don Stewart of the Marine Area Command at Coffs Harbour and recommended the Ballina Marine Rescue crew be nominated for bravery awards.

Acting Insp Lilley said Mr Stewart said he would recommend the crew were honored for risking their lives to prevent a tragedy.

It is understood two men who are related were travelling south in the 36 foot motor cruiser when they went to shelter in the Richmond River and got into trouble in the rough seas on the Ballina sandbar.

The men sent out a distress signal at 12.20am and the Ballina Marie Rescue boat responded.

Acting Insp Lilley said both the men were from Tasmania and the boast was owned by another Tasmanian man.

At 1pm today police received reports that a vessel had been spotted about 800 metres south of the Ballina bar.

The location of the boat will be monitored and if it is confirmed to be the motor cruiser, a salvage operation may be conducted in the coming days.

There have been no reports about the location of the Ballina Marine rescue vessel.

UPDATE 11am: DESPITE a search this morning there remains no sign of the capsized Marine Rescue boat or the vessel it was trying to save when it flipped.

Elton Cummings, from the Ballina Jet Boat, said a crew had been searching for the vessels, but the water close to the coast was dirty and it would be impossible to see them if they were fully submerged.

"You'd hit it before you saw it," he said.

The Marine Rescue service last year spent $50,000 on the boat's first major repair in 12 years.

8.40am: FIVE people plucked from high seas off the coast of Ballina early this morning, including the crew of the town's Marine Rescue boat, were lucky to have been found at all, a spokesman for the Ballina Jet Boat has said.

Three of those people are now in Ballina Hospital after the Marine Rescue boat capsized while trying to save a motor cruiser, leaving them stuck on the vessel's hull for about an hour while a one stayed in an air pocket under the boat, Jet Boat spokesman Elton Cummings said.

The drama began about 1am this morning when the Marine Rescue was called to help a vessel struggling to get across the Ballina bar.

The Marine Rescue crew tried twice to attach a tow-rope to the cruiser, but each time the ropes got tangled in the vessel's propellers.

"Both boats were dragged out around the wall with the outgoing tide, and there was no time for the crew to do anything," Marine Rescue NSW regional coordinator Stephen Reading said.

"They got hit by a couple of big waves and they were on the rocks."

Mr Reading said the Marine Rescue crew and two people from the stricken vessel were thrown into the water when the rescue boat flipped over.

Mr Cummings said the Jet Boat was called out about 2am to rescue the two crews.

At that point, the seas were running at between two metres and three metres, making it difficult to spot the cruiser, the marine rescue boat, which was, by then, about two kilometres off shore, or the flashing beacons on the crew members' life jackets.

"It was only luck we found them upside down," Mr Cummings said.

There were concerns about one person who remained under the boat and Mr Cummings said one of the Jet Boat crew was about to jump in the water to find him "when he just popped up".

The five people were transferred to the jet boat but, with that many people aboard and conditions so rough, Jet Boat skipper Mark Puglisi had decided they would not able to get safely back across the Ballina bar.

The Westpac Life Saver Rescue Helicopter had also been called out, but was unable to winch the rescued crew members to safety in the rough conditions.

By then it was about 3am and some of the Marine Rescue crew were sufferingh hypothermia and showing signs of going into shock, so calls were flying to find another rescue boat that could take some of the rescued crew across the bar, or another helicopter that could winch them out in the rough conditions.

"We called the Water Police, we called the Evans Head Coast Guard and they couldn't get through the Evans Head bar," Mr Cummings said. "No boats could get out, it (the sea) was just too big."

Finally, about 4am, skipper Mark Puglisi felt the rescued Marine Rescue crew could wait no longer and made the decision to run the jet boat ashore at Shelly Beach, where ambulance crews were waiting to take them away.

As for the cruiser and the capsized Marine Rescue boat, both remain at sea.

Mr Reading said the Marine Rescue boat was upside-down and half-sunk off Lighthouse Beach.

It was not known whether it could be salvaged.

"Rescues in the dark and in bad conditions are always treacherous," he said. "Everyone is very shaken up."

* An earlier version of this story reported eight people had been rescued, the number of people rescued was actually five, putting a total eight people in the Jet Boat after the rescue. The earlier version also described the vessel that was originally in trouble as a yacht. We have now been told it was actually a motor cruiser. The story has been updated to correct this information.